Heartburn drugs linked to increased pneumonia risk

NEW YORK (Reuters Health) - People on two types of widely prescribed heartburn medications may have a higher-than-average risk of developing pneumonia, a new research review finds.

The drugs in question belong to two classes frequently used to treat heartburn or stomach ulcers: proton pump inhibitors, which include drugs like Nexium, Prevacid and Prilosec; and H2-receptor blockers, such as Pepcid and Zantac.

In the U.S. alone, people spent $27 billion on these medications in 2005.

Some studies have found a connection between the heartburn drugs and a heightened risk of pneumonia. One theory is that by curbing stomach acid, the medications allow ingested bacteria that would otherwise be killed to instead survive and thrive -- and potentially get into the lungs.

For the new analysis, South Korean researchers pulled together 31 international studies looking at the connection between heartburn drugs and pneumonia.

When they combined the studies' results, they found that people on either proton pump inhibitors or H2 blockers were about one-quarter more likely than non-users to develop pneumonia.

Some studies focused on people who became infected while in the hospital, where pneumonia is a common, and often deadly, problem. Other studies focused on out-of-hospital infections. People who used heartburn drugs were at increased risk in either case.

The risks to any individual medication user were not huge. The researchers estimate, for example, that among hospital patients on the heartburn drugs, there would be about 25 cases of pneumonia per 1,000 patients. That compares with 20 cases per 1,000 among hospital patients not on the drugs.

And it's not certain that the drugs themselves are to blame, Dr. Sang Min Park, one of the researchers on the study, told Reuters Health in an e-mail.

It's possible that chronic acid reflux itself could at least partly account for the link, according to Park, of Seoul National University Hospital. Acids that back up out of the stomach can sometimes be sucked into the airways, where they could cause pneumonia.

Still, Park said the findings suggest that doctors and heartburn sufferers should use some caution when it comes to acid-suppressing drugs.

Discuss the pros and cons with your doctor, the researcher advised, and use the medications only if necessary to control your symptoms -- in cases where diet and other lifestyle changes don't work, for example -- and at the lowest dose possible.

Caution would be especially important for people already at higher-than-average risk of pneumonia, such as the elderly and people with emphysema or other chronic lung diseases, according to Park.

The findings, reported in the Canadian Medical Association Journal, are based on 31 studies from Europe, Asia and North America.

Based on the hospital studies, Park's team estimates that acid-suppressing drugs could contribute to an extra four to five cases of pneumonia for every 1,000 hospital patients.

The researchers point out that anywhere from 40 percent to 70 percent of hospital patients are on one of these drugs. This, they say, suggests that the medications could account for a "considerable" portion of hospital-acquired infections.

The researchers could not perform a similar overall estimate for out-of-hospital infections. But one study they reviewed gives an idea of the drugs' potential contribution to pneumonia cases outside hospitals.

In that study, Dutch researchers looked at out-of-hospital pneumonia rates among nearly 365,000 adults over seven years. Of the people on proton pump inhibitors or H2 blockers, 2.5 percent developed pneumonia per year, versus 0.6 percent of those not on the drugs.